A new study shows that a lot of growers and extractors aren’t taking the steps to keep nasty contaminants out of your wax and bud.

“There’s a stereotype, a hippy kind of mentality, that leads people to assume that growers are using natural cultivation methods and growing organically,”  Andy LaFrate, founder of Charas Scientific, a lab certified to test marijuana in Colrado. “That’s not necessarily the case at all.” LaFrate’s results were unveiled at the American Chemical Society (ACS) in Denver earlier this week.

“It’s pretty startling just how dirty a lot of this stuff is,” LaFrate told Smithsonian Magazine. His lab found a significant amount of fungus and bacteria in the weed they tested. “Like ourselves, this plant is living with bacteria that are essential to its survival. In terms of microbial contamination, it’s kind of hard to say what’s harmful and what’s not… So the questions become: What’s a safe threshold, and which contaminants do we need to be concerned about?”

The article in the Smithsonian also argued that some extraction methods preserve heavy metals, pesticides, and other contaminants while burning off the harmless chemicals in marijuana.

“People use all kinds of different methods to produce concentrates,” LaFrate says. “But what grade of solvents are they using? Are they buying heptane on eBay, and if so, what exactly is in there? There are a whole bunch of issues to figure out, and right now there are not enough resources and really no watchdog.”